The present invention relates to a replacement tread for automobile truck tires, aircraft and other pneumatic tires. Presently, retreaded tires are tested for high speed performance, endurance and impact, the latter being commonly referred to as plunger testing. Many retreaded tires fail under one or more of the present testing procedures. Many of these failures can be attributed to improper use of fixed matrices which unduly stress the retreaded tire and to a non-uniform massive buildup of rubber-like base stock which results in a heat buildup while a tire is in service.
Under a commonly used prior art retreading operation, fixed matrices or molds are utilized to mold the new tread design into uncured rubber which has been secured to a prepared tire casing. Subsequently, the assembly is vulcanized to cure the tread rubber and bond it to the tire casing.
Since the 1950's when nominal sizes of passenger tires were generally uniform in both construction, sectional configuration and tread widths, tire companies have begun to produce many sizes, sectional configurations and constructions of tires. In addition, the advent of belted tires and radial constructed tires has resulted in tire casings which are relatively inflexible. Therefore, to properly retread passenger tires using the still popular matrix system, numerous matrices must be purchased by a tire retreader in order to properly retread a tire. The use of a tire matrix which is noncompatible with a particular tire casing to be retreaded often results in the above-identified failures.
Another prior art method of retreading tires, particularly truck tires, has been the use of a precured tread which has its ends joined together to encircle a prepared tire casing. The entire assembly is then placed in a flexible envelope. Vulcanization is subsequently performed by placing the assembly in an autoclave under heat and pressure.
Considerable difficulties are encountered in such a method of retreading tires to positively prevent the entrance of air between the precured tread stock and the adjacent surface of the tire casing.
Another tread for recapping tires is disclosed in U.S. Pat. No. 3,283,795. A precured tread section having a bottom radius of curvature greater than the radius of curvature of the tire casing is applied to the tire casing. When a strip is placed around the tire casing, the end faces of the new tread material are abutted against each other. This patent also discloses the use of several segmented circular rings or integral annular members, which are joined together during the retreading of a single tire.
This type of sectional retread has been used on large truck and off the road tires.